Fluid-operated reciprocating machine tool



. March 18, 1930. J. L. HOLMAN ET AL 1,750,890

FLUID OPERATED RECIPROCATING MACHINE TOOL Filed May 9, 1925 2 Shouts-Sheet 1 Fig.1.

March 18, 1930. J. L. HOLMAN ET AL 1,750,890

FLUID OPERATED RECIPROCAIING MACHINE TOOL Filed May .1925 Quota-Shani IRVINTOR 3 Patented Mar. 18, 1930 Arts- UNITE JOHN LEONARD HOLMAN AND ARTHUR TBEVE 'HoLMAN, or oAMBoR-Nn, ENGLAlND,

ASSIGNORS TO HOLD/IAN BROTHERS LILIITED, G CAMBORNE, ENGLAND, A BRITISH COMPANY FLUID-OEERATED EECIPROGATING MACHINE TOOL Application filed May 9, 1925, Serial No. 29,108, and in Great Britain October 16, 1924.

object of the invention is to provide a tool of minimum overall length.

According to a primary feature of this invention the reciprocating'valve comprises a tubular shell, preferably having a reduced middle portion constituting an annular recess anda core of resilient or shock-absorbing material (for example, india-rubber). Preferably, the end faces of the core are recessed in such manner (for example, coneshaped) that fluid-pressure acting on the said fa'cestends to expand the coreto forma fluid tight seal with the tubular shell. The form of the valve after heat-treatment is such that the fibre ofthe materialis longitudinal and therefore in the direction to resist impact which ensures maximum durability.

According to another feature of theinvention the valve-chest is 'constituteclby a sleevelike member having ports (for example, radial'ports) in its wall arranged to co-operate with ports in the walls of a chamber in which the said'sleeve-like member may be also provided with passages in its periphery which are completed by the walls of the chamber. In this manner the passages for the operating fluid are made asshort as possible which is very desirable to secure the utmost efficiency.

In order to reduce the overall length of the tool the handle-portion thereofis according to another feature of thls invention recessed to constitute a portion of thelworking cylinder for the reciprocatmg piston. The said recess may be provided with a liner which constitutes one wall of an annular fluid-supply passage extending round the recess.

According to a feature of the invention there is provided between two parts (for example between the handle portion and the cyl1nder casing) between which a fluid-tight joint is desired, a joint ring composed of fibre or of other packing or jointing material which will enable a close and fluid-tight joint to be obtained. 1

In order that the invention may be'more clearly understood one preferred construction of riveting hammer will now be described, by way of example only with the aid of theaccompanying drawings in which- Figure 1 is a longitudinal central section through the hammer; I I

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3- is a section on the line 3-3 of Figure 1 but drawn to a scale twice as large as that of Figure 1; V

Figure 4: is a sideelevation of a cylindrical block which fits within the valve chest and is also drawn to a scale of Figure 1; .7

Figure 5 is'a section corresponding to that of Figure 1 and illustrating diagrammati cally'the corresponding parts of Figure 1. In this figure the various invention.

in the several figures.

twice as large as that ports; are all shown in the one plane; and y Y .ergure 6 illustrates a modificationof thef The following description, referringito the 7 construction illustrated in Figures 1 to 4: can be followed'in Figure 5 wherefsimilar refeii ence-letters are employed. The handle 10 is provided with the usual trigger-controlled throttle valve 11 the trigger of which. is shown at 12. The valve '11 a dmi'ts the drivin'g'fluid, for example @ompress i air, from themain supply conduit 13 by way'of a port' formed also in the body ofthehandlel A liner 16 constitutes theinn'er'wal'l of the recess 15 and also serves as anextension of the working cylinder to bereferred to later.-

The joint ring is preferably composed of no l l'in thehandle to an annular recess 15,-

fibreor. other packing "or jointing material:

which vwill'enable a close and fluid-tight joint to be obtained between it and the handle I .on one side and the cylinder casing 19 on the other side.' The material may be, such as to be slightly compressible so'that the parts on either side" can become slightly embedded in'it.

tral bore 22. extending partially'through it and constitutingv a chamber for a'reciprocat The-ports 17 in the cylinder 05515-919 communicate with an annular groove 20 formed ina valvechest 21., The valve chest comprises a cylindrical block having a cening valve 23'. The block 21 is fixed in a chamber adjacent the working cylinder 24' and-conveniently above it. The groove 20 is the rear end of the block 21 and the latter 7 is formed with ports 25 which, when the valve 23 is inits forward position, place the groove 20 in communicatlon with the lnterior of the valve-chamber, that is the bore in the block 21.

Theigroove isa-lso communication with a port26 (Figures 4 and 5) in the forward end of the-valvechamber by way of a longi-tudinal passage 27 in the periphery of the block 21 Theport 26 opens into a portion of the valve chamber which is reduced in diameter and this portis never covered by the valve-so that the, driving fluid exerts a constant pressure on the-forward end ofthe',

' valve.-

' A by-passvp-assage28 connects the forward end of the workinggcylinder 24 with the ...valve .c'hest chamber inthe casing 19 and is. [connected with the valve chamber by means ot grooves 29 (-Eigur'es4 and 5) 'andports 30 'and 31"formed in the: valve chest 21.

fCo nvenientlyfthe valve chest is formed.

withtwo fia ts. 32 (Figures "3 and 4) in which the ports 1.30 'and f3l drilledz The ports 30- thusf ;op,e'nhintorecesses bounded at one sideby'theflatsand at the other sideby the outer casing and are uncovered. by the l forward. end of the valve 23:when in its rear- -"wa;rd position and the other ports 31 arejun-f covered, when the valve fits forward sages29.v

" position, to communicate with reduced mid;

dlefportion of the valve. Itwillbe seen that the. flatslg32 communicate with the. pas- There is additional 15bit 33.;(Figures. 4'

. and .5) connecting. the longitudinal passage 27 withthe forward end of the valve cham; v ber and'this portis uncoveredwhen the valve o isfin its. rear position. Thus, assumingthe working'pis'tonf34 to bein its forward posi- 1 tionfand the valve 23 in its rearward posttion, driving fluid is freely admitted by way of the passage 27,;ports, 26, 33 and-30 and grooves 29fto the passage 28 leading into the'r' 'forward e'nd of, the working cylinder 24.

-- The'gpiston is'fthiis movedrearwardly. The

provision {of .oneor moreports 33 fpre vents' thatthe'vailv'e 23Tcomprises' a tuhulargshell 141 pressed up from thin .s'heet'metalfand filled: with "a core of resilient orTyieIding material 2 i such as india-rubber. end faces of the 7 core are recessed 'sothat when, the fluid pres sure acts on them theyitendtoexpandto form a'fiuid-ti'ght seal with the tubu lar sh el-lL" In; a modification of theinven'tion', 'illus:

wire-drawing of'the. fluid flowing to the front end of the valve, which mightoccur if only the port 2 6were provided.

A main exhaust port 35 is formed in the wall of the cylinder 24" and communicates withfa; passage "36 leading to the rearof the tool where a number of outlet holes 37' are provided In the particular example illustrated there are two .ports 35 .andtwo chan= nels 36 terminating two sets of outlet holes 37. v i i 1 When the. rear end ofthe piston 34 in 1ts backward movement covers the exhaustport:

35 the compressed air or otherdriving fluid trapped in the rear end of the cylinder 24;

becomes'compressed to suchan'extent as eventually to overcome the constant pressure :act

ing on the forward end oiithe valve 23 thus driving the valve forward. It will be seen that the rear end of the cylinder 24 is in'communication with the rear end of the valve chamber through a port 38; formed in -the,

joint ring 18; During the travel of the:pis-- ton 34 rearwardlyjthe iiorward end of the piston. uncovers the ports thus permitting driving fluidwhich was previously admitted through the'passage 28 to escape. to atmos'- phere. The; piston, however, continues to 3 move rearwardly due to its ;momentum-.

When the; valve is; reversed as aforesald wardly to strike ablow on the tool 39. When the piston uncovers, ,by its rear end, the ports 35,- driving'fluid 'fromthe back-of the piston E to g ' that ismoved forwardly to. the other end of its; stroke from the position shown in Figures ,1 and 5,-the'ports 30 and 33 are closed and admission of driving fluidlto the forward end of theeylinder 24 is cutvofi and the driving fluid is admitted to the rear; end through the" I port38. The piston 34 isthen driven for 1 suddenly escapes and the pressure on the rear face o fthevalve 23 drops; Thecon-z stant pressure acting 1 on the forward face ofthe, valve; through the port 26 drives the I iio valve bacliwardly and the cycle offoj ports 40' which communicate with'cne of the exhaust-passages 36 It w-"ll be. seen in the j e'x'ample "illustrated pe n above described. is then repeated, I

lit

trated in Figure 6, the handle 10 is in hooked or open form and the fluid supply is taken direct from a passage 140 in the handle direct through the port in the jointringlS to the valve chamber without passing through an annular passage round a cylinder extension such as 16. In this case the extension 16 is not hushed as in the example illustrated in Figure 1 Referring to the joint ring it is to be observed that it may be of any preferred material not necessarily of fibre as referred to hereinbefore. For instance, it may be composed of an asbestos-graphite composition; or it may be formed of lead or even of other metal which is not necessarily readily compressible.

The provision of such a joint ring has a considerable advantage in that the machining of the faces of the two parts between which it is disposed need not be carried out with such accuracy as would be necessary if the two parts were to be held together face to face so as to give the required fluid-tight: ness of the joint between them. Also when the joint ring becomes damaged or worn so that it is no longer sufficiently serviceable to maintain the fluid-tight joint it may be readily replaced, and its replacement is a matter of very small expense. Another advantage is that the faces of the joint ring, when it is made of the material into which the adjacent parts can be somewhat embedded, require no machining and the joint ring can be stamped, moulded, or otherwise formed according to the nature of the material employed. 7

Although specific forms of the invention have been described in detail it is obvious that modifications in construction may be made, without departing from the invention,

according to the type of tool under consideration.

We claim 1. The combination of a valve chest formed as a tubular sleeve adapted to fit in an outer casing and having in its outer periphery at one end an annulargroove whereof one Wall is constituted by a flange at said end of the chest, which groove has an admission port connecting it with the interior of the chest, which chest has a recess in its periphery near the other end thereof, a passage for conveying driving fluid connecting said recess with the adjacent end face of the chest, and a port for connecting said recess with the interior of the chest, and a fluid-actuated reciprocatory valve in said chest for controlling said ports, which valve comprises a tubular shell and a core of yielding material in said: shell.

2. The combination of avalve chest formed as a tubular sleeve adapted to fit in an outer casing and having in its outer periphery at one end an annular roove whereof one wall is constituted by a connecting it with the interior of ange at said end of the 'chest, which groove has an admissionport situated towards the latter end of the chest- I in a part of its periphery circumferentially remote from said recess, and a conduit con necting said groove with the latter port, and a fluid-actuated reciprocatory valve in said chest for controlling said ports, which valve comprises a tubular shell and a core ofyielding material in said shell.

3. The combination of a valve chest formed as a tubular sleeve adapted to fit in an outer casing and having in its outer periphery at one end an annular roove whereof one wall is constituted by a f ange at said end of the chest, which groovehas an admission port which chest has a flat-loottomed recess in its periphery near the other end thereof, a passage for conveying driving fluid connecting said recess with the adjacent end face of the chest, and a port in the flat bottom of said recess for connecting said recess with the interior of the chest, and a fluid-actuated'reciprocatory valve in said chest for controlling said ports, which valve comprises a tubular shell, and a core of yielding material in said shell. I

4;. The combination of'a valve chest formed as a tubular shell adapted to fit in an outer L casing and having in its outer periphery at one end an annular groove whereof one wall isconstituted bya flange at said end of the chest, which groove has an'admission port connecting it with the interior of the chest, which chest has a recess in its peri hery near the other end thereof, a passage or conveythe chest,

ing driving fluid connecting said recess with"v the adjacent endface of the chest, and two ports connecting said recessiwith the interior of the chestat the-latter end, and a'fluid actuated reciprocatory valve in said chest for 1 controlling said ports, which'valve comprises a tubular shell, and-'a'core of yielding material in "said'shell, which two ports in said re cess are arrangedspaced apart inthe direction ofmovement of the valve, and one thereof is open'and the other closed by the valvein an end position of the latter. j

5. The combination'of a valve chestformed as a tubular shell adapted to fit in-an outer casing and having in its outer periphery at oneend an'annular groove whereofone wall is constituted by 'a flange at said end ofthe chest, which groove has an admission port connecting it with" the interior of the: chest,

which chest has a'recess in its periphery near 7 the other end thereof, a passage for conveying driving fluid connecting said recess with the adjacent-end face of the chest, andtwo ports connecting said recess-With the interior 7 i I of thechest at the latter end, and a fluid-ac- Q recess'are anrangedspaced apart in the direc tion-ofino'vement of the valve, and one thereteri'alj-in saidshell, which two ports in said of is open andthe other'c'losed bythe valve an end position'ofthelatter a conduit in sa d chest connected at one endto said groove, and

I another vport in'lsaid chest connected to the other end; of said conduit and opening into the chest at sncha position that it is closed by the valve in an endposition of the latter When one o-if'thetwo ports aforesaid is closed, but is openedvjvhen that-port isopened a 4 9 For use in a fluid-operated machine-tool, the combination ofa valve chest having an admissionport at one end and an-end Wall at p L I 1166101L of length i of the chest, and acoird nit in the periphery ot the chest connecting the other end, tWo portsspaced apart in the diIFBQtiOn-Of length of the ohest'at-the latter end, andaneXhan-st port at the middle of the chest-,5 ai'fiuidactuated valve reciprocable in said -chest in the direction: of length thereof, which valve has a recessed iniddle portion arrange'd to open communication with said ex-:

V haust-{port'and-theinner of said two ports,

jwhie'h; ZChQS't-ha's a conduit that opens'at 'one end into the admission sport" aforesaid and at the OthQIKQ IICllS-QJWQYS in open communication with the interior'Iof the chest throngh a Vnamesto specification. f I

' chest, which yehesthas at'the latter'end fthereof another v -pOlft opening 1 into the interior thereof olitsidgapf said recess, and a conduit connecting :the' latterport; W-lth said groove.

9; ;Eo r 'nse in a fluid-operated machine tool, a tubular valve "chest havingin its outerpe ripheryat one vend thereof an annnlar groove ln-issionport connecting it with the interior of the chest,'vvhich chest has an end Wall closing the other vend thereof and hassituated to,'

opens into theexternal face of the adjacent whereof one Wall is con-stituted by a flange at one end of the'chest, which groove has anlad= end wall of the chest,.Whichchestihas in said 7 recess adelive'ry port and an eXhaus'tipo-rt,

spaced-aparti-i'i the direction :of length of'the chest viihich chesft tnrtherhas atthe lat-trzend thereof ftvvo other; ports spaced apart in the the' latter ports with said groove, one 0f chest;' 1

e In testimony-whereoi (we-have signed our whichllattergports opens into 1 a recess formed r a Lineman: mania i -AR lHU-n TR vE HOLMAN.

1 port'inothe said end wall thereof, whiteh ehest further hrasapjortcontrolled byz's'aid valve 4 eonnectifng the end -of'the chestadjacentthe 1 l-attenpor't. withdsai-d-conduitq onegend an i annular groove whereof one Wall iSzQQnstitnt-ed byaifiange at one end of the p 1 7131? r nseinj fluid-operated: machine-tool, avalveohest having inits outer peripheryat 7 r QWith-the interior oithe oh-estytvhich chest-has the chiest,

, sit natedwtowards'the-fother-reiid ther eOf ane -I ternaliiperiplieralirecess' oonnected bya' pas; V

,o sa e-'withijthe-ad a enteziternalfendLface'of" hiohvchesth as si-titated towards the latter end'ithereof tvvo admission portsopeng 'f' V ing'feachi'nto the in'te'rior'iof theichest, one'of; I

' 8;.rFor use in a fiuid operated;machineetool,

a tubular valve chest having in its-outer periphery;atone end an annular groove Whereoi l one allis ,constituted'by a flan'geiat one end Jof thefchest, which groovehas an admission 1 v r, V --portconnecting?.itwiththexinterior ofithe chest; which chest has situated towards theif "other-'end-{thereof an external peripheral "recess eonnectedby passage With the'Eada Lja'cent externalzendfaceof the chest,-ahd-itwev portsrconnectingsaid recess wi thitheinterior Q ofjthe achest,,whichltwoportsarearranged spaced'apart-inthe direction of lengthz'd fzthei and izof V 

